So, what to do about it? My dad suggested that I put old sheets on the flowers overnight. I do have old sheets, but they are the ones that I use. I looked up what else was recommended online. The site I visited suggested first of all to only plant flowers that could withstand frost, not helpful! I already put down lots of impatiens. It also suggested watering them well beforehand, which I would not have guessed. And, of course, covering them with plastic, sheets, or something. I took most of the sheets we own outside. Just look how ghetto! Keep your fingers crossed that the flowers survive.
And, in other gardening problems, apparently both animals think the back garden is a big litter box. How do I stop that?